Molecular simulation study on permeation behavior of small molecules in graphyne/polypyrrole mixed matrix membrane

The research on the permeation behavior of small molecules in mixed matrix membranes (MMMs) is an important part of the research of MMMs. Graphyne, a new two‐dimensional carbon material, was used as the filler, and polypyrrole was used as polymer matrix to construct a MMM. In order to clarify the permeation behavior of common small molecules in MMM at room temperature and constant pressure, the adsorption and diffusion properties of H2O, CO2, and O2 in graphyne/polypyrrole MMM were investigated by combining the Giant Canonical Monte Carlo (GCMC) and molecular dynamics (MD). The results show that: (1) the order of adsorption capacity of the three molecules is H2O > CO2 > O2; (2) the diffusion ability of the three molecules is influenced by the doping content of graphyne. Oxygen diffusion and permeation in MMMs are optimal when the graphyne filling level is 15%. The filling of graphyne affects the permeation of gases. It will shed light on application areas such as coating membranes for electronics in special environments, gas separation membranes, and gas sensor membranes. Highlights A new two‐dimensional carbon nano filler—graphyne was used. A simulation method using a combination of GCMC and MD. The diffusion and permeation behaviors are analyzed from multiple perspectives. The permeation behavior conforms to the solution‐diffusion theory. The graphyne‐filled MMM is conducive to oxygen molecular diffusion. Polypyrrole chain model, Graphyne nanosheet model, 1yne‐ppy mixed matrix membrane model and 1yne‐ppy mixed matrix membrane with adsorbed water molecules. (Green structure schematic graphyne nanosheet structure).